Actually, this natural immunity fallacy has been around a long time: Great Barrington Declaration. Too many people were dying before vaccines were available. There is a huge contrast between states in the US where vaccine hesitancy is high and states with 60% or more of adults vaccinated. This shows pretty conclusively that vaccination is necessary. Natural immunity wanes and may not stand up to new variants.
One good thing is that people who have had Covid and are then vaccinated, with even only a single jab, have incredible immunity, far surpassing a double jab in those who have